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The calibration process of a multispectral camera is fundamental for analyzing images where color standards must be referenced in a post-processing stage. This work presents a new method to process images acquired with a multiband/multispectral camera and scanned for reflectance information with a commercial spectrophotometer. The strategy implemented is based on a general illumination model describing lighting as an image component that changes depending on the captured environment and reflectance as a component depending only on the object's surface. Since the relationship between intensity, luminance, and reflectance in a captured image is not linear. A novel general result is that illumination adjustment generates a valid reflectance map with better surface information. An equalization of reflectance components using RGB model separation to standardize the same pixel value for each of the images was performed on eight certified Lucideon Std ceramic tiles. Lighting of 6000k was used to perceive color similar to normal daylight to each tile, both data captured in the same position. Possible industrial applications of the proposed methodology include reducing time and complexity in color inspection, multispectral image processing, and obtention of better color surface representations under various lighting conditions and application requirements. Particularly, this work shows image results interpreted in CIE RGB color space where B12 has values ​​of 44, 61, and 63; B11 has values ​​of 141, 176, and 84; B10 has values ​​of 214, 176, and 203; B9 has values ​​of 123, 89, and 82; B8 has values ​​of 201, 66, and 225; B7 has values ​​of 86, 73, and 103; B6 has values ​​of 22, 37, and 160; B5 has values ​​of 108, 107, and 64. Those compared to values measured by an spectrophotometer as reference device were in good correspondence, achieving percentage calibrations of ∼ 100 % . [ABSTRACT FROM AUTHOR]

Tetradesmus is a microalgal genus with biotechnological potential due to its rapid production of biomass, which is plenty in proteins, carbohydrates, lipids, and bioactives. However, its morphology and physiology need to be determined to guide better research to optimize the species cultivation and biocompounds processing. Thus, this study describes the biochemistry and morphology of the strain Tetradesmus obliquus BR003, isolated from a sample of freshwater reservoirs in a Brazilian municipality. In the T. obliquus BR003 dry biomass, we identified 61.6% unsaturated fatty acids, and 3.4% saturated fatty acids. Regarding other compounds, 28.50 ± 1.47 g soluble proteins/100 g, 0.14 ± 0.009 g carotenoids/100 g, 0.76 ± 0.013 g chlorophyll a/100 g, and 0.42 ± 0.015 g chlorophyll b/100 g with a chlorophyll a/b ratio of 1.8 were detected. The main chemical elements found were S, Mg, and P. The cells of BR003 were elliptically curved at the ends and without appendages. Histochemical tests showed carbohydrates distributed in the cytoplasm and pyrenoids, some lipid droplets, and proteins. The cytoplasm is rich in vacuoles, rough endoplasmic reticulum, mitochondria, and chloroplasts. The nucleus has a predominance of decondensed chromatin, and the cell wall has three layers. Chloroplasts have many starch granules and may be associated with a spherical central pyrenoid. To the best of our knowledge, this was the first biochemical description combined with ultrastructural morphological characterization of the strain T. obliquus BR003, grown under standard conditions, to demonstrate specific characteristics of the species. [ABSTRACT FROM AUTHOR]

Student evaluation of teaching (SET) questionnaires are the most common methods of evaluation used by European universities to assess the quality of teaching delivered by their lecturers. A series of multivariate statistical methods were applied to analyze the underlying structure of the SET questionnaire used by the Universidad Politecnica de Valencia (UPV) in order to develop an appropriate methodology for extracting, analyzing, and interpreting the information contained in the questionnaire. In a first step, a confirmatory factorial analysis (CFA) was developed in order to evaluate the reliability, validity and dimensionality of it, by means of two relatively new parameters commonly used in structural equation modelling: the compound reliability and extracted variance for each latent construct. In a second step, cluster analysis (CA) was used to test the ability of the questionnaire for the identification of different categories of lecturers. In the last step, a tree classification method, the chi-squared automatic interaction detector (CHAID), was used in order to characterize the different lecturer's categories obtained with CA according to all available information regarding the teaching staff and subjects. [ABSTRACT FROM AUTHOR]

Understanding the neurobiological processes that contribute to the establishment and expression of stress-induced regulation of cocaine use in addicted individuals is important for the development of new and better treatment approaches. It has been previously shown that rats self-administering cocaine under long-access conditions (6 h daily) display heightened susceptibility to the reinstatement of extinguished cocaine seeking by a stressor, electric footshock, or i.c.v. administration of the stressor-responsive neuropeptide, corticotropin-releasing factor (CRF). This study tested the hypothesis that adrenal responsiveness during earlier long-access cocaine self-administration (SA) is necessary for the establishment of later CRF-dependent stress-induced reinstatement. Reinstatement by footshock, but not a cocaine challenge (10 mg/kg, i.p.) following long-access SA, was blocked by i.c.v. administration of the CRF receptor antagonist, α-helical CRF9−41 (10 μg). Elimination of SA-induced adrenal responses through surgical adrenalectomy and diurnal corticosterone replacement (ADX/C) before 14 days of SA under long-access conditions had minimal impact on cocaine SA, but blocked later footshock-induced reinstatement. By contrast, ADX/C after SA, but before extinction and reinstatement testing, failed to reduce footshock-induced reinstatement. Likewise, ADX/C before 14 days long-access SA prevented later reinstatement by i.c.v. CRF (0.5 or 1.0 μg). However, significant CRF-induced reinstatement was observed when rats underwent ADX/C following SA, but before extinction and reinstatement testing, although a modest but statistically nonsignificant reduction in sensitivity to CRF's reinstating effects was observed. Taken together, these findings suggest that adrenal-dependent neuroadaptations in CRF responsiveness underlie the increased susceptibility to stress-induced relapse that emerges with repeated cocaine use. [ABSTRACT FROM AUTHOR]

This paper presents a new method to obtain an approximation of the field of movements of 1-DOF linkages with lower pairs. The method is based on a linkage representation by natural coordinates and the storage of the constraint equations by means of a sparse cubic matrix. To obtain a discrete approximation of the field of movements, a three-stage process is used. In the first stage, a special Evolution Strategy is applied to make the population converges towards the zones where the constraints' error is minimal, obtaining, at the same time, a good distribution of individuals. In the second stage, the final individuals of the ES are used as initial points for an optimization algorithm to obtain a greater accuracy. Later, the third stage is a filtering process to eliminate individuals that represent non-desired solutions. This method has been tested on some linkages with well-known fields of movements, generating comprehensive outcomes that justify the validity of the method. [ABSTRACT FROM AUTHOR]